506 PFEIFFER'S BACILLUS 



venous inoculation and were able to demonstrate a multiplication of the 

 bacilli in the blood and in the pulmonary and renal lesions. 



Kruse produced sub-cutaneous abscesses and found living bacilli in the 

 pus. Slatineano, and Delius and Kolle infected rabbits by intra-peritoneal 

 inoculation. Cantani, Slatineano, and Martin, set up a fatal disease by inocu- 

 lating small doses of culture into the brain. 



Mixed infections. Rosenthal inoculated a mixture of Pfeiffer's bacillus and a 

 non- virulent staphylococcus aureus into rabbits' lungs : the animals died " of pul- 

 monary congestion generally accompanied by septicaemia." Jacobson produced a 

 fatal infection accompanied by generalization of the bacillus by inoculating rabbits 

 intra-venously with a mixture of streptococci and Pfeiffer's bacillus. 



Guinea-pigs. Guinea-pigs are almost insusceptible but can be infected 

 by intra-peritoneal inoculation of very virulent cultures (Delius and Kolle, 

 Elmassian, Cantani and others). 



Mice. Mice die from toxaemia after intra-peritoneal inoculation of large 

 doses of culture. Infection may also be produced by intra-peritoneal inocula- 

 tion of small doses of virulent cultures, or by mixing the bacillus with a 

 sterilized culture of streptococci (Jacobson). 



SECTION II. MORPHOLOGY. 

 1. Microscopical appearance. 



Pfeiffer's bacillus is a very small rod-shaped organism with rounded ends, 

 having practically the appearance of a cocco-bacillus. It is one of the smallest 

 visible micro-organisms, is non-motile, and occurs singly or arranged in small 

 chains composed of two to four bacilli. In sputum the bacilli are often seen 

 massed together in large numbers. The organism is sometimes found within 

 the leucocytes. In cultures, it is a little larger and longer than in sputum. 









FIG. 243. Pfeiffer's bacillus Sputum Dilute FIG. 244. Pfeiffer's bacillus. Film from 



carbol-fuchsin. (Reich, oc. IV, obj. ^th.) a blood-agar culture. Dilute carbol-fuchsin. 



(Reich, oc. IV, obj. T Uh.) 



Klein lays stress upon the frequency with which long strepto-bacillary filaments 

 and bacilli with a central vacuole are seen in cultures. He has also noticed involu- 

 tion forms : long sinuous bacilli sometimes looking like a tangled mass of filaments, 

 as well as large oval or club-shaped bacilli. 



Staining reactions. Pfeiffer's bacillus does not stain very readily with 

 the basic aniline dyes and is gram-negative. The best method is to stain with 

 dilute carbol-fuchsin for about 10 minutes. Carbol-methylene blue, carbol- 

 thionin or Nastikow's violet may also be used. Staining may be accelerated 

 by heating the dye. 



